Macromolecular interactions between proteins and nucleic acids appear to be a fundamental feature of biological systems. With the primary structural and physical characterization of the molecular components of the procaryotic protein synthetic apparatus nearly completed the opportunity to investigate the molecular basis for such associations which occur within this system is now possible. The object best suited for this work is the bacterial ribosome in which an excess of ten unique ribosomal protein and rRNA complexes have been identified. Within the scope of current technology it will be possible to examine at the level of primary structure those portions of ribosomal proteins which interact with small sequences of ribosomal RNA. It is proposed here that, because of the ubiquitous nature of the ribosome, a systematic primary structural identification of the components involved in these associations will yield general principals for nucleic acid and protein interaction within the protein synthetic apparatus even in the broadest phylogenetic gaps. It is further hoped that the effort will transcend the ribosome itself and yield insight into such events as replication and transcription of nucleic acids, viral assembly, etc. Although the principle goal of this work will be to identify the primary structural features of interacting proteins and nucleic acids, it is anticipated that an enhanced perception of the biochemical ultrastructue of the bacterial ribosome will be gained. This will not only yield a better comprehension of the topological and functional relationships between the macromolecular components of the ribosome itself, but a more detailed understanding of bioassembly process. BIBLIOGRAPHIC REFERENCES: Jenness, D., Bruce, J., Schaup, H. W. Nucleic Acids Res. 3, 1 (1976).